Carburetor throttle control



Dec. 3, 1940. LE. COFFEY CARBURETOR THROTTLE CONTROL Original Filed June24, 1937 2 Sheets-Shet 1 INVENTOR. [EVE/V 5. Cor/2y Waugh/Z ATTORNEY.

Y L E. COFFEY CARBURETOR THROTTLE CONTROL Dec. 3, 1940.

Original Filed June 24, 193'? 2 Sheets-Sheet 2 H R F w mwa N C m 5 T V WM Reissued Dec. 3, 1940 UNITED STATES CARBURETOR- THROTTLE CONTROL IrvenE. Coffey, Normandy, Mo., assignor to Carter Carburetor Corporation, St.Louis, Mo., a corporation of Delaware Original No. 2,148,729, datedFebruary 28, 1939,

Serial No. 150,187, June 24, 1937.

Application for reissueJune 8, 1940, Serial No. 339,581

16 Claims.

This invention relates to carburetors for automobile engines andconsists particularly in novel throttle control means therefor.

Modern automotive carburetors are usually provided with means forincreasing the richness of mixture supplied when the associated engineis being subjected to abnormally heavy loads. Such condition is.ordinarily accompanied by substantial opening of the throttle valve andrelatively low suction in the intake passages. The additional richnessmaybe obtained by means for increasing the effective size of the mainmetering orifice or by a device for opening an auxiliary fuel supply tothe mixture conduit and the auxiliary enrichener may be controlledmanually with the throttle valve or by means of a suction actuatedmechanism. In the case of a manual enrichener such as athrottle-controlled, stepped metering rod cooperating with the mainmetering orifice, the power step of the metering rod must necessarily bebrought into operative relationship with the metering orifice wheneverthe throttle is opened to the predetermined degree regardless of therate of speed or the load applied to the engine. The additional richnessprovided by the power step at low speeds is essential for obtainingmaximum power from the engine, but during acceleration and high speedoperation, this extra richness accounts for so only slight if anyimproved performance and is not essential.

The average automobile driver rarely subjects his engine to conditionsrequiring maximum power and, accordingly, seldom actually needs theadditional richness which accompanies full opening of the throttlevalve. Such a driver is ordinarily not sufliciently skilled to operatethe throttle valve in the most economical manner, though it could be sooperated without noticeably affecting the operation of his car.Consequently, when he desires rapid acceleration or increased power, hedepresses his throttle pedal much more than is necessary and wastesfuel. Substantial opening movement of the carburetor throttle valve atan excessive rate, as the driver is frequently prone to do, particularlyin traffic, has the additional disadvantage that the engine cannotrespond at a corresponding rate and, consequently, the suction in theengine intake may drop excessively, with the result that the engine mayaccelerate at a slower rate than would have been the case if thethrottle had been opened more gradually.

An object of the present invention is to provide means for selectivelylimiting the degree to which the carburetor throttle valve may beopened.

Another object is to provide manual means for varying the effectiverelationship between the throttle and its control pedal or lever.

Another object is to provide automatic means for limiting the degree towhich the throttle valve may be opened when normal driving conditionsprevail while permitting greater or full opening of the throttle underother conditions.

Another object is to provide means for making operation of the throttlevalve easier for city or other driving when repeated variation of thethrottle position is necessary. v

Another object is to provide operative mechanism for connecting thethrottle pedal and throttle valve incorporating a resilient device forpreventing opening of the throttle valve at a rate faster than theengine can respond.

Still another object is to provide novel throttle operating mechanismdesigned to function as an anti-stall device.

These objects and other more detailed objects hereafter appearing areattained substantially by the devices illustrated in the accompanyingdrawings, in which:

Fig. 1 is a view, partly in section, showing parts of an internalcombustion engine and carburetor control mechanism therefor. v

Fig. 2 is a view of the mechanism taken on line 2-2 of Fig. 1, theflooring being omitted.

Fig. 3 is a section taken substantially on line 3-3 of Fig. 2.

Fig. 4 is a view similar to Fig. 1, but showing a modification. I

Fig. 5 is a diagrammatic representation showing operative parts of acarburetor and another form of the invention.

Fig. 6 diagrammatically illustrates still another form.

Figs. 1 and 4 show a portion of internal combustion engine I, of theusual automotive type. having exhaust manifold 2 and intake manifold 3merging in hot spot construction 4 for applying exhaust heat to theintake gases. Mounted on the hot spot is a carburetor, generallyindicated at 5, having a throttle valve 6 mounted near the outletportion thereof. As shown in Fig. 5, the carburetor also includes adowndraft mixture conduit at I, venturis 8, choke valve 9, and mainnozzle l0. Adjacent the mixture conduit is a constant level chamber llhaving the usual float controlled inlet valve mechanism (not shown).Fuel is supplied to main nozzle ll] through metering orifice member l2and accelerating fuel rock lever l9 connected at one end with thethrottle arm H by means of a link 20. The opposite extremity of lever I9is provided with a slot 2| which slidably receives the bent over endportion 22 of push rod 23 secured at its upper end to the usualthrottle. control pedal 24. Rod 23 passes through an opening 25 in theflooring 26.

A plntle 21 depending from a portion of flooring 26 spaced laterallyfrom rock lever l9 pivotally mounts a lever 28 extending substantiallyat a right angle to lever l9 and paralleling flooring 28. Lever 28 isyieldably held in position against flooring 26 by a coiled spring 28which also prevents rattling. This lever has an opening 30 at one endloosely receiving throttle push rod 23 and an upstanding toe 3|extending through a slot 32 in the flooring in position to be actuatedby contact of the drivers foot.

Push rod 23, in Fig. 1, is at the inner extremity of slot 2| in whichposition full movement of pedal 24 to the dotted line position shownfully opens the throttle valve. In case the operator wishes to obtainmaximum economy which accompanies restriction of the degree to which thethrottle may be opened, lever 28 may be manually rotatedcounterclockwise, with reference to Fig. 2, so as to move push rod 23 tothe outer extremity of slot 2|. Such movement increases the leveragerelationship between the throttle valve and its control pedal, or, inother words, varies the mechanical advantage of. the throttle controlmechanism so that full movement of pedal 24 produces only partialopening movement of the throttle valve. Obviously the maximum degree towhich the throttle may be opened by the pedal may be varied by merelymoving push rod 23 to difl'erent positions in slot 2|. With rod 23 atthe outer end of slot 2|, the throttle valve can be opened only to theposition indicated in Fig. 5 with the larger or socalled economy step ofmetering rod l4 still restricting metering orifice.

In Fig. 4 the throttle control mechanism-is the same as that shown inthe previous form, and a modified form of mechanism, for varying themechanical advantage between the throttle valve and its control pedal isshown. This mechanism comprises a suction actuated device shownconventionally at 33, in which a diaphragm (not shown) is normally urgedto the right by a spring. The suction device is connected to intakemanifold 3 by means of a tube 34 in which is inter posed a manualshutoff valve 35. Suction device 33 operates a rod 36 which is connectedby means of a pivoted lever 31 to a reach rod or link 38 having anaperture 38 loosely receiving throttle push rod 23. This rod is shown insolid lines at the outer end of slot 2| to which position it is movedwhen relatively high suctions prevail in the intake manifold. In thisposition of parts, the throttle valve is only partially opened, asindicated at 6a, when pedal 24 is fully depressed.

Fig. 4 also shows in dot and dash lines the throttle push rod moved tothe inner end of slot 2| to permit full operation of the throttle, suchmovement being effected when suction in the intake manifold drops belowa predetermined value. Valve 35 provides for manually cutting offsuction applied to suction device 33, whereupoon push rod 23 will bemoved to and held in the broken line position.

The calibration of the suction device and con nections shown in Fig. 4varies with diiferent engines. Preferably, device 33 should move rod 23from the solid line position in Fig. 4 to the broken line position whenthe suction in the intake manifold drops from a value corresponding to,say, eight to ten inches of mercury to a value corresponding to four toseven inches of mercury. Thus, when the suction in the intake manifoldexceeds the top suction limit mentioned, wfhich condition prevailsduring most normal driving, the throttle connections will be adjustedfor the most economical operation. In case, how-' ever, the intakesuction drops, as when the engine issubjected to an abnormal load or thethrottle is opened quickly, push rod 23 will be automatically slid alongslot 2| to permit a greater opening of the throttle valve. Such a movement of the push rod will also occur in case the engine speed tends tobecome slower and the throttle pedal is held stationary with the resultthat the throttle will be automatically opened and additional powerprovided.

Figs. 5 and 6 illustrate diagrammatically hydraulic or pneumaticarrangements for operating the throttle valve. In Fig. 5, a valve 48controls the branched fluid connection between primary cylinder 4|,receiving piston 42 connected to throttle pedal 24 and secondarycylinders 43 and 44 having pistons 45 and 46 connected to throttle arm Hby balance lever 41 and link. Valve 48 has an operating handle 49 easilyaccessible to the driver of the vehicle for connecting primarytube 50with either of the tubes 5| or 52. When cylinder 4| is opened tocylinder 43 by means of valve 48, full depression of pedal 24 fullyopens the throttle valve. In case valve 48 is set to connect the primarycylinder to cylinder 44, which is larger than cylinder 43, full movementof the pedal operates the throttle valve only to the partially openposition shown with the economy step of the meteringrod still in themetering orifice, as explained above.

In Fig. 6, a suction device 53 somewhat similar to that in Fig. 4communicates through tube 54 with the fluid connection 55 connectinghydraulic cylinders 56 and 51. Piston 58 in cylinder 56 is connected topedal 24 and piston 53 in cylinder 51 is connected to throttle arm l1.

A spring loaded check valve 65 in tube 64, has a restricted centralaperture 66 whereby the valve impedes movement of the hydraulic fluidfrom the suction device into connection 55 but offers substantially noresistance to passage of the fluid through tube 54 in the oppositedirection.

When a substantial drop occurs in the intake suction communicated todevice 53 through conduit 6|], spring 6| moves diaphragm 62 upwardly.This movement forces a part of the fluid from the suction device intotube 55 and cylinder 56 fully raising piston 58 and pedal 24. When thesuction device is thus discharged, so to speak, full depression of pedal24 operatesthe throttle throughout its full range. When the engine stopsand pedal 24 is released, spring 6|, being stronger than either spring63 or spring 64, forces still more fluid into connection 55 elevatingpis-. ton 59, since pedal piston 58 at the top end of its stroke, andslightly opening the throttle preparatory to restarting the engine. Suchautomatic reopening of the throttle occurs as slowly as desirable due tothe restriction at check 55. Because of this feature, the device is alsoeffective to prevent stalling while the engine is idling. Under suchconditions, diaphragm 62 ordinarily would be drawn downwardly by thehigh idling suction, but any reduction of this suction, as in case theengine starts to hesitate prior to a stall, will be accompanied. bycorresponding expansion. of spring BI and opening of the throttle toaccelerate the engine due to forcing of liquid into cylinder 51.

When the intake suction is relatively high, as is the case under mostnormal driving conditions, diaphragm 52 will be lowered against spring6|, drawing fluid from connection 55 into the suction device.Thereafter, until the suction again drops, the throttle pedal will beonly partially raised when the throttle is fully closed by its returnspring and consequently depression of the pedal from such position canonly partially open the throttle.

The device 53 constitutes a resilient chamber for receiving a part ofthe hydraulic fluid when the throttle pedal is depressed at a rapidrate, regardless of the suction effect upon the diaphragm 62, andthereafter discharging the same gradually into the hydraulic line. Assuch, the device prevents the throttle valve from being opened toorapidly, a desirable function since when the throttle is quickly opened,the suction in the engine intake system drops very low, due to theinability of the engine to accelerate at a corresponding rate. As aresult, the rate of fuel discharge from the carburetor nozzle is sharplyreduced and such fuel as is supplied by the carburetor may collect onthe walls of the intake manifold, instead of being carried into thecylinders by the airflow. Accordingly, the engine will actuallyaccelerate faster if the throttle valve is opened at a moderate ratewhich approaches the rate at which the engine will respond, than if thevalve is more quickly opened. The insertion of the collapsible chamber53 into the hydraulic line permits the driver to depress the pedal asrapidly as he likes to obtain acceleration at the maximum rate, withoutexperiencing substantially increased resistance to the pedal action.

The invention is shown applied to a type or carburetor having a meteringrod controlled manually with the throttle valve and the adjust ment ofsuch device obviously depends upon the relationship between the throttlevalve and the power step of the fuel metering rod. Where the inventionis used with the suction step-up type of carburetor, adjustment of thevarious mecha nisms will depend on the suction condition in the intakeor carburetor at which the suction step-up device is arranged to providethe increased richness. Suction device 33 should move rod 23 to theinner end of slot 2| before the intake manlfold suction dropssufliciently to cause functioning of the auxiliary enriching device. Anexample of a form of suction step-up device is shown in a co-pendingapplication of Leland B. Read, Serial No. 129,786, filed March 9, 1937.The invention is adapted for application to all types of throttlecontrolled, internal combustion engines.

An additional advantage of the invention results from the fact thatvarying the mechanical advantage of the throttle control mechanism notonly limits the extent to which the throttle valve may be opened butalso makes opening of the valve against the throttle return spring (notshown) substantially easier. The invention contemplated broadly varyingthe mechanical advantage of the throttle control mechanism, however,effected.

Various parts of the structures shown are not essential and these may bemodified as will occur to those skilled in the art. The exclusive use ofall such modifications as come within the scope of the appended claimsis contemplated.

I claim:

1. In combination, a carburetor throttle valve element, a manual controlelement therefor, and mechanism for varying the operative relationshipbetween said elements comprising a pivoted lever having a recess, a linkconnecting one oi said elements with a portion of said lever spaced fromsaid recess, and a link extending from the other of said elements tosaid recess and movable therein to vary the leverage relationshipbetween said elements.

2,. In combination, a carburetor throttle valve, a manual controlelement therefor, a pivoted lever having a slot, a link connecting saidvalve with a portion of said lever spaced from said slot, a second linkconnecting said control element with said slot, and structure extendingfrom said second link and accessible with said control element formoving said second link in said slot to vary the operative relationshipbetween said control element and said valve.

3. The combination of elements specified in claim 2 constructed andarranged so that full movement of said control element is capable ofmoving said throttle valve only to a partially open position when saidsecond link is in a predetermined position in said slot.

4. In combination, a carburetor throttle valve element, a controlelement therefor, a pivoted lever having a recess, a link connecting oneof said elements and a portion of said lever spaced from said recess, asecond link connecting the other of said elements with said recess, anda suction actuated device connected to said second link for moving thhesame in said recess to vary the operative relationship between saidcontrol and valve elements.

5. In an internal combustion engine, intake structure including acarburetor mixture conduit, a throttle valve element in said conduit, acontrol element for said valve, leverage mechanism connecting saidelements, and means including a member responsive to suction in saidintake structure for varying the mechanical advantage of said mechanismto vary the operative rela tionship between said elements.

6. The combination of elements specified in claim 4 in which saidmechanism and said means are constructed and arranged so that whenrelatively high suctions prevail in said intake structure, full movementof said control element produces only partial opening movement of saidthrottle valve element.

'7. In combination, a carburetor throttle valve, fluid pressuremechanism including a manual control for operating said valve, and meansfor varying the effective relationship between said control and saidvalve, said mechanism including separate devices operable to providedifferent operative relationships between said valve and said control,said means functioning to render said devices selectively operative.

8. In combination, a. carburetor throttle valve, a manual controltherefor, a primary fluid pressure device connected to said control, apair of secondary fluid pressure devices connected to said valve, andconstructed and arranged to variably translate fluid pressurestransmitted from said primary device, fluid connections between saiddevices, and valve means for selectively connecting said primary deviceto said secondary devices.

9. In combination, a carburetor throttle valve, a manual controltherefor, a fluid pressure operative connection between said valve andsaid control, and a suction operated device for selectively withdrawingfluid from said connection and returning the same thereto according tosuction conditions in the intake of an associated engine.

10. Structure as specified in claim 9 in which said suction operateddevice functions to vary the effective size of said connection accordingto suction conditions in the intake of an associated engine.

11. In combination with an internal combustion engine, a carburetorthrottle valve, a manual control therefor, and means selectivelyresponsive to operative conditions in the engine for varying theeffective relationship between said valve and said control, said meansbeing constructed and arranged to partially open said valve when theengine is inoperative.

12. In combination with a carburetor throttle valve, a manual throttlecontrol, an hydraulic system forming an operative connection between thethrottle and said control, and a resiliently expansible and contractiblechamber member communicating with said system for receiving a part ofthe fluid therein when said control is actuated whereby the consequentmovement of the throttle occurs at a slower rate than the correspondingmovement of said control.

13. The combination as specified in claim 12 in which the resilience ofsaid chamber member is adapted to permit entry of fluid thereinto fromsaid system only when said control is actuated faster than apredetermined rate whereby movement of said control at such faster rateproduces relatively slower movement of thethrottle valve.

14. The combination specified in claim 12 further including a checkvalve in the communication between said system and said chamber memberdisposed to seat under the influence of fluid flow from said chambermember to restrict said flow and to unseat under the influence of theinfluence of fluid flow into said member.

15. In combination with a carburetor throttle member, a manual controlmember therefor, and passaged structure forming an hydraulic operatingconnection between said members, said structure including a resilientlyexpansible portion yieldable when greater than a predetermined pressureexists in said structure for retarding the response of said throttlemember to movement of said control member.

16. In combination with an internal combustion engine, a carburetorthrottle member, a manual throttle control member, an hydraulicoperating connection between said members, expansible and contractiblechamber structure communicating with said connection, a suctionconnection between said structure and the engine intake whereby enginesuction tends to expand said structure, and spring means opposing thesuction effect upon said structure and adapted to contract saidstructure when the engine suction drops so as to force fluid into saidconnection and open the throttle member.

IRV'EN E. COFFEY.

